Electrochemical elements, such as a lithium battery, an electric double layer capacitor, a lithium-ion capacitor and a molten salt battery, have been widely used as power supplies for portable microelectronics such as mobile phones and laptops, or for hybrid electric vehicles (HEV) or electric vehicles (EV), and further improvements in capacity and cost-reduction have been desired as high functionality and wide applications of these appliances.
For these electrochemical elements, generally, an electrode in which a mixture layer containing an active material is formed on a metal foil is used. For example, in the case of a positive electrode for a lithium secondary battery, as shown in FIG. 4, an electrode 31 for a lithium secondary battery, in which positive electrode mixture layers 33 containing a positive electrode active material such as a lithium cobalt oxide (LiCoO2) powder, a binder such as polyvinylidene fluoride (PVDF) and a conduction aid such as a carbon powder are formed on both surfaces of a current collector 32 made of an aluminum (Al) foil, is employed (e.g., Patent Literature 1).
Similarly, an electrode for a lithium secondary battery, in which a negative electrode mixture layers containing carbon (negative electrode active material), a binder and a conduction aid are formed on both surface of a current collector made of, for example, a copper (Cu) foil, is employed for a negative electrode.
Further, the positive electrode, the negative electrode, and a polyethylene resin microporous membrane, serving as a separator, are combined with the microporous membrane interposed therebetween to configure a lithium secondary battery.